Hydraulic cylinders are used in many industrial applications, such as in robotics, heavy machinery, garage doors, and the like. Often, a pair of hydraulic cylinders, separated by a gap or attached at two different parts of an object, are employed to move the object. In the case of an object that is constrained to move in a certain way, misalignment of the cylinders can damage the object, the cylinders, or other components related to the object or cylinders. Misalignment can occur for a number of reasons, including a loss of hydraulic pressure, different relative temperatures, or the like.
Garage doors of the swing-type are typically comprised of a door that remains in a single panel configuration even when the door is being opened and is open. Such doors are often opened and closed using hydraulic cylinders. These swing-type doors are typically of either unitary construction, or are manufactured in sections that must be assembled when the door sections are delivered to an installation site, requiring additional time and effort to assemble the door.
Doors have certain stresses that act on them as they open and close. Among the stresses include gravity and other forces related to the opening and closing of the door. For example, when a door is opened, a sudden movement of the hydraulic cylinders can place a large amount of force on the door at the location of attachment to the cylinders and at far ends of the door, that is, parts of the door furthest from external support, such as the bottom of a closed door in a substantially vertical position. These stresses can lead to sudden failure of the door, or, more likely, increased wear and fatigue to the materials of the door, that can eventually lead to failure, warping, and the like, which contribute to problems with the door such as poor fit and closure, and misalignment when closed or open.
Further, hydraulic cylinders do not always operate at the exact same pace. That is, two seemingly identical cylinders of identical size, can have different operation in that one cylinder may extend faster or slower than the second cylinder, or the like. When cylinders operate at different rates, the single-piece or rigid door can be subjected to even more stress, such as twisting stress and the like. If the cylinders get too far out of alignment with respect to each other, the door could even bind in the opening, or be damaged, such as by cracking or breaking. This can be expensive and potentially dangerous depending upon the degree of damage, the size and weight of the door, and the like.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for improvements in swing type door bracing, trussing, and load distribution.